Freezing and thawing can be hard on the interior of a home, they're not made like an RV. You can get condensation inside as well if the humidity level is up when the you shut off the heat. It doesn't take a much to maintain a temp of 45-50, especially since no one will be opening doors to go in and out. We kept the heat on in our cottage in Caseville, MI, ~1000 sq ft. Cost was minimal, you have a basic charge whether you use any power or not. Just wasn't worth the effort to drain the plumbing and remove everything that could freeze and bust. Plus we did go up in the winter on occasion.